The popularity of cementless total hip replacement
(THR) has surpassed cemented THR in England and Wales. This retrospective
cohort study records survival time to revision following primary
cementless THR with the most common combination (accounting for
almost a third of all cementless THRs), and explores risk factors independently
associated with failure, using data from the National Joint Registry
for England and Wales. Patients with osteoarthritis who had a DePuy
Corail/Pinnacle THR implanted between the establishment of the registry
in 2003 and 31 December 2010 were included within analyses. There
were 35 386 procedures. Cox proportional hazard models were used
to analyse the extent to which the risk of revision was related
to patient, surgeon and implant covariates. The overall rate of
revision at five years was 2.4% (99% confidence interval 2.02 to
2.79). In the final adjusted model, we found that the risk of revision
was significantly higher in patients receiving metal-on-metal (MoM:
hazard ratio (HR) 1.93, p <
0.001) and ceramic-on-ceramic bearings
(CoC: HR 1.55, p = 0.003) compared with the best performing bearing
(metal-on-polyethylene). The risk of revision was also greater for
smaller femoral stems (sizes 8 to 10: HR 1.82, p <
0.001) compared
with mid-range sizes. In a secondary analysis of only patients where body
mass index (BMI) data were available (n = 17 166), BMI ≥ 30 kg/m2 significantly
increased the risk of revision (HR 1.55, p = 0.002). The influence
of the bearing on the risk of revision remained significant (MoM:
HR 2.19, p <
0.001; CoC: HR 2.09,
p = 0.001). The risk of revision was independent of age, gender,
head size and offset, shell, liner and stem type, and surgeon characteristics. We found significant differences in failure between bearing surfaces
and femoral stem size after adjustment for a range of covariates
in a large cohort of single-brand cementless THRs. In this study
of procedures performed since 2003, hard bearings had significantly
higher rates of revision, but we found no evidence that head size
had an effect. Patient characteristics, such as BMI and American
Society of Anesthesiologists grade, also influence the survival
of cementless components. Cite this article:
